KVM: arm64: Remove PtrAuth guest vcpu flag

The vcpu flag GUEST_HAS_PTRAUTH is always associated with the
vcpu PtrAuth features, which are defined per vm rather than per
vcpu.

Remove the flag, and replace it with checks for the features
instead.

Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20241216105057.579031-16-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Fuad Tabba

arch/arm64/include/asm/kvm_emulate.h

@@ -691,9 +691,4 @@ static inline bool guest_hyp_sve_traps_enabled(const struct kvm_vcpu *vcpu)
 {
 	return __guest_hyp_cptr_xen_trap_enabled(vcpu, ZEN);
 }
-
-static inline void kvm_vcpu_enable_ptrauth(struct kvm_vcpu *vcpu)
-{
-	vcpu_set_flag(vcpu, GUEST_HAS_PTRAUTH);
-}
 #endif /* __ARM64_KVM_EMULATE_H__ */

arch/arm64/include/asm/kvm_host.h

@@ -866,10 +866,8 @@ struct kvm_vcpu_arch {
 #define GUEST_HAS_SVE		__vcpu_single_flag(cflags, BIT(0))
 /* SVE config completed */
 #define VCPU_SVE_FINALIZED	__vcpu_single_flag(cflags, BIT(1))
-/* PTRAUTH exposed to guest */
-#define GUEST_HAS_PTRAUTH	__vcpu_single_flag(cflags, BIT(2))
 /* KVM_ARM_VCPU_INIT completed */
-#define VCPU_INITIALIZED	__vcpu_single_flag(cflags, BIT(3))
+#define VCPU_INITIALIZED	__vcpu_single_flag(cflags, BIT(2))
 
 /* Exception pending */
 #define PENDING_EXCEPTION	__vcpu_single_flag(iflags, BIT(0))
@@ -965,7 +963,8 @@ struct kvm_vcpu_arch {
 #define vcpu_has_ptrauth(vcpu)						\
 	((cpus_have_final_cap(ARM64_HAS_ADDRESS_AUTH) ||		\
 	  cpus_have_final_cap(ARM64_HAS_GENERIC_AUTH)) &&		\
-	  vcpu_get_flag(vcpu, GUEST_HAS_PTRAUTH))
+	 (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_ADDRESS) ||       \
+	  vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_GENERIC)))
 #else
 #define vcpu_has_ptrauth(vcpu)		false
 #endif

arch/arm64/kvm/hyp/nvhe/pkvm.c

@@ -278,18 +278,6 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc
 		   allowed_features, KVM_VCPU_MAX_FEATURES);
 }
 
-static void pkvm_vcpu_init_ptrauth(struct pkvm_hyp_vcpu *hyp_vcpu)
-{
-	struct kvm_vcpu *vcpu = &hyp_vcpu->vcpu;
-
-	if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_ADDRESS) ||
-	    vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_GENERIC)) {
-		kvm_vcpu_enable_ptrauth(vcpu);
-	} else {
-		vcpu_clear_flag(&hyp_vcpu->vcpu, GUEST_HAS_PTRAUTH);
-	}
-}
-
 static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu)
 {
 	if (host_vcpu)
@@ -359,7 +347,6 @@ static int init_pkvm_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu,
 		goto done;
 
 	pkvm_vcpu_init_sve(hyp_vcpu, host_vcpu);
-	pkvm_vcpu_init_ptrauth(hyp_vcpu);
 done:
 	if (ret)
 		unpin_host_vcpu(host_vcpu);

arch/arm64/kvm/reset.c

@@ -211,10 +211,6 @@ void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
 		kvm_vcpu_reset_sve(vcpu);
 	}
 
-	if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_ADDRESS) ||
-	    vcpu_has_feature(vcpu, KVM_ARM_VCPU_PTRAUTH_GENERIC))
-		kvm_vcpu_enable_ptrauth(vcpu);
-
 	if (vcpu_el1_is_32bit(vcpu))
 		pstate = VCPU_RESET_PSTATE_SVC;
 	else if (vcpu_has_nv(vcpu))